In SAP S/4HANA, Service and System user types are excluded from some general password-related rules, such as password validity periods or initial password requirements. Service Users, often used for web-based access or anonymous logons, do not require frequent password changes or initial password setups, as their access is typically managed via certificates or system configurations, reducing administrative overhead. System Users, designed for background processes like batch jobs, also bypass these rules, as they are not intended for human interaction and often use system-generated or fixed credentials for automated tasks. Dialog Users, used for interactive human access, are subject to strict password policies, including validity and initial password requirements, to ensure security. Communication Users, used for machine-to-machine interactions, may have specific authentication mechanisms but are generally subject to password policies unless otherwise configured. Excluding Service and System Users from these rules supports operational efficiency while maintaining security, as their non-interactive nature reduces the need for frequent password management.